2.2 Data source
JMDC data includes patient-level demographic information, inpatient and outpatient data—such as diagnosis and procedures—and prescriptions. Claims data are collected from clinics, hospitals and pharmacies; these records are traceable even when an enrollee utilizes different healthcare providers. Prescriptions, procedures, admissions, and the beginning of medical care are indexed by date. All diagnoses are coded using International Classification of the Diseases, Tenth Revision (ICD-10) code, along with Japanese standardized diagnostic codes. The latter provide more detailed information than ICD-10 code, such as influenza virus type (eg, type A, type B or unspecified). All prescriptions refer Anatomical Therapeutic Chemical Classification System code together with brand name, and procedures are encoded using Japanese-specific procedure codes.